It is generally accepted that positional vertigo might result both from lesions in the central nervous system and from lesions in the peripheral vestibular organ. In 1921, Bardny described a characteristic paroxysmal vertigo and nystagmus occurring in a certain critical position, and he suggested that the pathogenesis of this condition was related to otolith disease. In 1952, Dix and Hallpike described positional vertigo of the benign paroxysmal type (BPPN) due to a disorder of the otolith.
This nyatagmus is very characteristic and nowadays is widely accepted among clinicians as a nystagmus due to otolith lesions. Furthermore, this characteristic nystagmus has become one of the most reliable signs for diagnosing vertigo due to disorder of peripheral vestibular organs. Although there have been numbers published papers describing positional vertigo due to lesions within the central nervous system (Bruns, 1902 ; Alpers and Yaskin, 1944 ; Allen and Fernandez, 1960 ; Fernandez and Alzate, 1960 ; Sakata u. a., 1979 ; Sakata, Ohtsu and Takahashi, 1984), most of these cases are not of the benign paroxysmal type.
Recently, we have treated several patients with typical nystagmus of the benign paroxysmal ty-pe due to lesions in the cerebellar vermis. We discussed the differential diagnosis of BPPN, Pseudo-BPPN and MPPN.

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To clarify the role of spatial orientation in maintaining balance during everyday activities, I present a spatial coordinates hypothesis and discuss the mechanisms controlling gaze, posture and locomotion. The self-space relationship may be recognized by reproducing surrounding space in the brain, irrespective of head movement, on the basis of perceiving gravity from the otolith endorgans, rotational and linear displacements from the semicircular canals and otoliths, and three-dimensional space from vision.
Control of stance and upright locomotion should resemble control of gaze, both of which seem to be accomplished by feedforward regulation of a biological index (the center of gravity, gaze) toward a target (supporting foot, vi-sual target). These mechanisms must be clari-fied from the viewpoint of cognition, prediction and simultaneous programming of multiple motor systems during voluntary actions.

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A 48-year-old female complained of severe rotatory vertigo. Downward vertical nystagmus was observed when her head hung down. Magnetic resonance imaging (MRI) showed left cerebellar infarction and vertebral angiography (VAG) showed occlusion of the left posterior inferior cerebellar artery (PICA). A bypass branch from the left vertebral artery (VA) below the foramen magnum was seen on VAG. If there is a bypass branch from the VA below the foramen magnum, vertical nystagmus may occur because of pressure on the bloodvessel by the edge of the foramen magnum, especially when the head is hanging down.
VAG was more useful than MRI in demonst-rating the occlusion of PICA in this case. A definite diagnosis aid in the choice of medication, in general advice about life style, and also in psychological counseling.

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Two patients with hereditary spinocerebellar degeneration with slow eye movements were examined with electronystagmography.
The results in case 1 were as follows:
a. Pursuit eye movements were intact in all directions.
b. Rapid eye movements were disturbed in both vertical and horizontal directions. Horizontal eye movements showed slower velo-city than vertical ones.
c. Optokinetic nystagmus (OKN) in the horizontal direction showed a square wave pattern without a fast component.
d. In caloric tests, oscillatory eye movements were recorded during irrigation of both ears. In the visual suppression test, decreased fixation suppression was observed with cold water irrigation of the left ear, while normal fixation was obtained with irrigation of the right ear.
e. Upward nystagmus was elicited by bilateral irrigation with cold water.
The results in case 2 were as follows:
a. The velocity of rapid eye movements decreased, especially in the horizontal direction.
b. The fast phase of, OKN was absent except for upward OKN.
c. In caloric tests with cold water, the eyes deviated to the stimulated side.
A review of the literature suggests that the site of lesions responsible for slow eye movements is the paramedian pontine reticular formation or its afferent fibers.

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Tests of visual fixation during head movements were evaluated.
The subjects were asked to fix a visual target while the head was oscillated. Head and eye movements and the sum of both movements were recorded with a polygraph and stored in a microcomputer. From the stored data, transfer function was calculated with head movements as input and eye movements as output. As conditions of head movements, the following three head oscillations were studied. 1) "1 Hz method" in which the head was oscillated at 1 Hz ; 2) "acceleration-deceleration method", in which oscillation of the head started at 0.3 Hz, accelerated gradually until it was as rapid as possible, then decelerated gradually ; 3) "pseudo-random method", in which oscillation of the head was as random as possible.
In the "acceleration-deceleration method", visual fixation ability at 0.3 to 5 Hz was examined and the frequency at which failure of visual fixation occurred was easily noted, since the change of the frequency of head oscillation was sequential. Transfer function obtained from the "acceleration-deceleration method" was similar to that obtained from the "pseudo-random method".
These results indicate that the "acceleraion-deceleration method" is the best of the tests of visual fixation during head oscillation.

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The immunocytochemical localization of substance P (SP) in vestibular endorgans of various mammals (rat, guinea pig, rabbit, squirrel monkey, and man) was investigated. SP-like immunoreactivity was found in all the vestibular endorgans studied. Most SP immunoreactive fibers were thick and distributed around or beneath sensory hair cells. A smaller group of SP immunoreactive varicose thin fibers was present in the stroma of vestibular endorgans, nerve trunks, and along blood vessels around the vestibular nerves. The former, probably corresponding to the afferent nerve endings of hair cells, was found predominantly in the peripheral region of each endorgan. There were no great species differences in staining patterns, except in rat vestibular endorgans, where numerous thin SP immunoreactive fibers were distributed beneath the sensory epithelium. SP immunoreactive fibers were also found in human vestibular endorgans, suggesting that SP may play an important role in human vestibular function.

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The therapeutic effect of Isosorbide was evaluated in 43 patients (20 males and 23 females) with Meniere's disease.
Vertigo was reduced in 24 patients (87%) after 8 weeks of treatment.
However, in some patients vertigo became worse and nystagumus was observed again.
A follow-up study of 24 patients treated for 2 or more years was analyzed by AAOO and A AO-HNS evaluation criteria.
According to the AAOO criteria, definite attacks were reduced in 9 patients (69%) who were under medication for more than 6 months, and 10 patients (91%) who were under medication for 6 months or less.
According to the AAO-HNS criteria, definite attacks were reduced in 10 patients (77%) who were under medication for more than 6 months, and in 10 patients (91%) who were under medication for 6 months or less. In the follow-up study, hearing was not improved, but tinnitus was reduced in 9 patients (38%).
While under medication, definite attacks still occurred in some patients.
In conclusion, further research is needed to determine the dosage of Isosorbide required for the treatment of Meniere's disease.

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In 1891 and 1896, Chiari classified malformations of the hind brain that caused congenital hydrocephalus. In this classification were three of the four types of malformations that are now included in the group of Anold-Chiari malformations. In type 1, the cerebellar tonsils and medulla are displaced caudally into the foramen magnum. The medulla is often elongated, and a meningomyelocele is rarely present. Symptoms are often first noted in adult life.
We report here a 46-year-old female with Arnold-Chiari malformation type 1 and review the literature on this subject. Neuro-otological examination of this patient revealed horizontal rebound nystagmus and down-beat nystagmus. The preoperative and post-operative findings indicated that:
1. Horizontal rebound nystagmus was due to bilateral lesions of the nucleus fastigii and dentate.
2. Down-beat nystagmus was due to lesions of the inferior brain stem and inferior cerebellum.

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Three studies were undertaken in order to clarify the incidence of autoimmunity in inner ear diseases.
In the first study, the records of 255 patients with Meniere's disease and 127 patients with bilateral sensorineural hearing loss of unknown origin (SNHL) were examined retrospectively for the presence of autoimmune disease. Autoimmune diseases of various types were found in 4.7% of those with Meniere's cases and in 0.8% of those with SNHL.
In the second study, 44 patients with unilateral Meniere's disease (unilateral patients), 51 with Meniere's disease with bilateral fluctuant hearing loss (bilateral patients), and 37 SNHL patients were tested for the following : ESR and CRP levels, immunoglobulin levels (IgG, IgM, IgA), complement levels (C₃, C₃, CH₅₀), and autoantibody levels (rheumatoid factor, anti-DNA antibodies, and antinuclear antibodies).
A significantly higher incidence of severe immunologic abnormalities was found in bilateral patients than unilateral or SNHL patients.
In the third study, the results of the second study were correlated with inner ear function (hearing levels and caloric test results in Meniere's disease patients, and hearing levels in SN HL patients). Bilateral patients with severe immunologic abnormalities had poorer inner ear function in both ears than did patients with no or slight immunologic abnormalities. No relationship was observed between immunologic abnormality and inner ear function in unilateral Meniere's disease or SNHL.
The results of the above investigations indicate the likelihood of autoimmune involvement in certain cases of Meniere's disease with bilateral fluctuant hearing loss, and suggest that Meniere's patients should be examined for immunologic abnormalities.

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Reflexes of cervical muscles during linear acceleration were recorded electromyographically in normal subjects stepping laterally or antero-posteriorly. Electromyographical activity was observed in muscles opposite to the direction of stepping : the contralateral splenius capitis muscle in lateral stepping, bilateral semispi-nalis capitis muscles in forward stepping and bilateral sternocleidomastoid muscles in backward stepping.
Contraction of the contralateral muscles during linear acceleration seems to be elicited by the vestibulo-spinal reflex, especially from the otolith organ, to keep head position.

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The mechanism of non-specific defense of the inner ear against foreign bodies was invetsigated in guinea pigs. K-562 myelogenous leukemia cells were injected into the guinea pig perilymphatic space through the round window membrane. The tumor cells survived in the perilymphatic space for 24 hours but cell multiplication did not seem to have occurred by that time.
Natural killer cells could not be detected in the perilymphatic space. The survival of the tumor cells suggests that a significant and powerful non-specific defense mechanism is not active in the inner ear within 24 hours.

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Eye deviation in the horizontal and vertical direction was studied with a topomapping system in normal subjects and patients with vestibular dysfunction in total darkness. The measurements were made under two conditions : (1) while looking straight ahead and (2) while moving the eyes up and down. Under the first con dition, the following results were obtained.
1. In 20 normal subjects, horizontal eye position deviated 3 degrees or less and the vertical position 4 degrees or less, without showing any particular tendency to deviate from the median point.
2. In normal subjects unilateral ice water irrigation caused the horizontal component to shift to the irrigated side in some subjects and to the contralateral side in others. The vertical component showed an upward deviation in most subjects, suggesting that this shift is caused by stimulation of the otolith organ.
3. In 9 patients with vestibular neuronitis, all patients showed horizontal eye deviation to the affected side, vertical eye deviation was upwards in 6 patients and downwards in 3. All 3 patients with downward deviation had hypertension, cerebral arteriosclerosis and reduced brainstem blood flow on the affected side, and one of them had an abnormal ABR. These results suggest that downward eye deviation represents vestibular neuronitis complicated by brainstem impairment, as reported by Corvera, Wennmo and Pyykko.
4. In patients with dead labyrinth, central compensation for eye deviation was examined with topomaps. The central nervous system's compensation was superior in the horizontal direction. It appears that 2 years are required for complete normalization of eye deviation. When the subjects moved their eyes up and down in total darkness, the following results were obtained.
1. In 10 normal subjects, the width of the horizontal eye deviation was greater than that observed while they were looking straight ahead. The horizontal component of the center of gravity, however, was not differerent from the topomap when they were looking straight ahead. Large interindividual differences were observed in vertical eye movements.
2. Topomapping was carried out in 7 patients who satisfied all of the following requirements : (1) equilibrium function tests revealed good vestibular compensation ; (2) the topomap with eyes looking straight ahead was normal or almost normal ; (3) unilateral vestibular dysfunction. In 5 subjects, the topomap was shifted to the affected side, and in 2 it was shifted to the healthy side.

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There are two types of optokinetic nystagmus (OKN) fast phase. One is the eye movement looking at a visual target passing in front of the test subject (type A), and the other is a reflex which resets the eye position after deviation by the slow phase (type B). We developed a new method of quantitatively analyzing these two types of OKN. Optokinetic stimulation is given to a test subject by projecting stripes with a 5 degrees visual angle width on a screen at 30 degree intervals. The visual target is accelerated at 1 deg/sec/sec up to 100 deg/sec. The OKN is recorded by ENG and analyzed with a PDPll/34 computer. Slow phase velocities, and fast phase amplitudes and velocities of each OKN are plotted on a correlogram. There are two types of OKN fast phase on the correlogram, one with a low correlation with slow phase velocity and the other with a high correlation. It is considered that the low correlation type OKN corres-ponds to type A and the high to type B.
In order to quantitatively analyze these two types, approximate regression lines of each type, {y=ax+b (x : slow phase velocity, y : fast phase velocity or amplitude) }, were computed by the minimum square method.
The normal limits of "a" and "b" were determined statistically from the responses of 30 normal subjects. In normal subjects the differences between the values of "a" and "b" in the low correlation type OKN and those in the high correlation type were quite significant. On the other hand, of those with normal responses of OKN elicited by a random dot visual target and caloric nystagmus, few had nystagmus of the low correlation type. In patients with ver-tebro-basilar insufficiency and cerebello-pontine angle lesions, the low correlation type of OKN was significantly reduced.

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The therapeutic effect of Tofisopam (150 mg/ day p.o) was evaluated in 39 patients with vertigo or dizziness. The subjective symptoms and objective findings were recorded before and four and eight, weeks after the start of treatment. After eight weeks there was marked improvement in 30.6%, moderate improvement in 19.4%, slight improvement in 41.7%, and no change in 8.3%. Clinical improvement was not quite so high after four weeks of treatment. There was no significant difference in response between peripheral vertigo and autonomic dysfunction. Clinical improvement tended to be slightly lower in patients over 50 years old than in younger patients and higher in females than in males.
Many subjective symptoms, as well as vertigo and dizziness, were also reduced, such as stiff shoulder, stiff neck, headache, paresthesia and feverish sensation. The objective signs which were greatly improved were : righting reflex and gaze and positional and positioning nys-tagmus. Schellong's test, which had been positive in ten patients, became nagative in eight of them. Only one patient had any side effects : abnormal liver function tests. Tofisopam is con-siderd to be useful in the treatment of vertigo and dizziness.

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